Process for preparation of oximes and resulting products

ABSTRACT

A new oxime mixture used as an extractant for metals, prepared from natural products containing alkylated phenols such as cashew nut shell liquid using mild reaction conditions, is expressed by the formula:  
                 
 
     The oxime mixture is suitable for extracting gallium from waste effluents from ore processing, such as Bayer liquor.

REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of Ser. No.09/623,126, filed Aug. 28, 2000, now abandoned. This application claimspriority from International Application No. PCT/BR99/00020, filed Feb.2, 1999, and Brazilian application No. PI 9800783-1, filed Feb. 27,1998, the disclosures of which are incorporated by reference as if setforth fully herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to the preparation of novel compounds usedfor the recovery and purification of metals. More particularly, thisinvention relates to novel ortho alkenyl/alkyl substituted phenyl oximecompounds prepared from natural product sources and processes forselectively separating and recovering of metals from waste effluents andother such aqueous compositions and mixtures containing copper, galliumor other metal ions.

[0004] 2. Description of the Related Art

[0005] The extraction of metals from minerals and their recovery fromaqueous compositions and mixtures containing copper and other metals areimportant commercial processes.

[0006] Several extraction methods have been developed for recoveringmetals values. Solvent extraction processes for the recovery of metalvalues have certain well recognized advantages over other recoverymethods, and such solvent extraction processes are increasing in numberand types of applications.

[0007] Fundamental to a successful solvent extraction process for therecovery of metals is the identification of water immiscible composition(combination of compounds which will selectively bind to the metal and asuitable solvent) which will selectively extract the metal from anaqueous solution containing copper, and other metals. A furtherrequirement for a successful metal recovery extraction techniques is anextracting composition having the property such that metal valuesextracted by the extracting solvent can be recovered from the same usinganother suitable aqueous phase.

[0008] Illustrative of such prior art solvent extraction processes arethose described in U.S. Pat. No. 3,967,956 and in United Kingdom PatentNo. 20 136 443. In the processes of these patents, palladium isrecovered from a mixture of palladium and other platinum group metalsthrough use of an extracting composition containing ortho hydroxy oximecompounds, such as alkyl substituted ortho-hydroxyphenyl oximecompounds. The extracted palladium metal is removed from the extractingsolvent by contacting same with a strongly acidic aqueous solution.

[0009] This method is generally a useful procedure for recoveringcertain metals from the extracting solvent because the recoveryprocedure is pH dependent. With ortho- hydroxy phenyl oxime compounds,the extraction process is dependent on the ionizable nature of thephenolic hydrogen, and in the Cu+² system is generally believed tofollow the following equilibrium in which “LH” is the un-ionized oxime:

SUMMARY OF THE INVENTION

[0010] In accordance with this invention there is provided a small classof ortho alkenyl/alkyl substituted phenyloxime compounds which areuseful in the extraction of copper, gallium and other metals. Thecompounds of this invention are of the formula:

[0011] where R₁=C₁₅H_(31-n) and n=0, 2, 4, 6.

[0012] R₁ is a mixture of one alkyl and three alkenyl hydrocarbonicradical substitutes localized at the benzenic ring of the substitutedphenyl aldoxime. That is, when n=0, R₁ is a substituent of the formulaC₁₅H₃₁. When n=2, R₁ is an alkenyl substituent containing one doublebond, represented by the following formula:

[0013] When n=4, R₁ is an alkenyl substituent containing two doublebonds, represented by the following formula:

[0014] When n=6, R₁ is an alkenyl substituent containing three doublebonds, represented by the following formula:

[0015] The invention uses mild reaction conditions so that the mixtureof R₁ substituents referred to above can be made from the cardanol foundin cashew nut shell liquid, which contains a mixture of moleculescontaining, no, one, two and three double bonds in the aliphatic lateralchain.

[0016] In addition to the aldehydes produced in accordance with thereaction scheme of this invention as precursors of aldoximes within thescope of this invention, ketones can be made by reacting anacardic acidwith organolithium compounds like CH₃Li, C₂H₅Li, C₃H₇Li and other suchorganometallic compounds, and then reacted like the aldehydes of thisinventions to produce corresponding ketoximes.

[0017] Our invention is particularly directed to the extraction ofgallium from waste effluents from the processing of aluminum-bearingores, such as bauxite, in which gallium naturally occurs. The liquideffluent from factories that process bauxite to extract aluminum,commonly called Bayer liquor, contains gallium and other metals. Zincminerals are also known to contain gallium and may be processed with theoximes of this invention for the extraction of gallium. The oximes ofthis invention also can be used to extract copper, nickel, silver,palladium, germanium and rare earth elements.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The compounds of this invention are mixtures of the formula:

[0019] wherein R₁ is C₁₅H_(31-n) and n is 0, 2, 4 or 6 as describedabove, and mixtures thereof.

[0020] The following compounds are illustrative of compounds within thepurview of the generic formula set forth above, all of which can beconveniently prepared by simply selecting appropriate natural productsfor the use in procedures described here in below:

[0021] (2-hydroxy,3-alkyl)phenyl aldoxime;

[0022] (2-hydroxy,3-alkenyl)phenyl aldoxime;

[0023] (2-hydroxy,4-alkyl)phenyl aldoxime;

[0024] (2-hydroxy,4-alkenyl)phenyl aldoxime;

[0025] (2-hydroxy,5-alkyl)phenyl aldoxime;

[0026] (2-hydroxy,5-alkenyl)phenyl aldoxime;

[0027] (2-hydroxy,6-alkyl)phenyl aldoxime;

[0028] (2-hydroxy,6-alkenyl)phenyl aldoxime.

[0029] Particularly preferred are compounds of the above referencedgeneric formula in which n is 0 and R₁ is straight chain alkyl having 15carbon atoms; n is 2 and R₁ is straight chain alkyl having 15 carbonatoms and one double bond between the 8- and 9-carbons; n is 4 and R₁ isstraight chain alkyl having 15 carbon atoms and two double bonds betweenthe 8- and 9-carbons and the 11- and 12-carbons 11 and 12; and n is 6and R₁ is straight chain alkyl having 15 carbon atoms and three doublebonds between the 8- and 9-carbons, the 11-and 12-carbons and the 14-and 15-carbons.

[0030] The compounds of this invention can be conveniently prepared by avariety of methods. One preferred method for preparing the compounds ofthis invention is illustrated in the following Reaction Scheme A:

[0031] Cashew nut shell liquid natural alkylated phenols are used asstarting materials to obtain aldehyde intermediates are submitted toreaction with hydroxylamine to produce corresponding aldoximes.

[0032] It is known that cardanol is present in cashew nut shell liquid,in concentrations of 5 to 10%, weight by weight, as mentioned in theliterature. On the other hand, it is also known that heating cashew nutshell liquid between 180 to 200° C., promotes the decarboxylation ofanacardic acid, its main component, transforming it into cardanol.

[0033] Fractional distillation under reduced pressure, at temperature of200° C. and 10-25 mm Hg, produces cardanol in yields up to 65% inweight, relative to the cashew nut shell liquid.

[0034] This cardanol is a mixture of saturated cardanol and unsaturatedcardanols as disclosed above.

[0035] On the laboratory scale, cashew nut shell liquid was distilledunder reduced pressure (10-25 mm Hg), at temperatures in the range of200 to 230° C. In a round bottom glass flask reaction with three necks,adapted to a refluxer condenser, addition funnels with pressureequalizer and magnetic stirrer, were added, under an inert atmosphere(N₂), 45 g of chloroform and 100 g of cardanol mixture distilled fromcashew nut shell liquid. The system was heated and 300 mL of a 4.6Nsodium hydroxide solution was added drop by drop, keeping on stirringand refluxing for six hours and thirty minutes, at 65° C. Afterreaction, the system is allowed to cool at room temperature.

[0036] Pure hydrochloric acid was added to the reaction mixture until apH of 1 was reached. The purpose of this reduction in pH is to improvethe yield of the reaction, transforming the by-product acetals insalicylaldehyde, and also promoting a good separation of organic andaqueous phases.

[0037] The organic layer was separated from the aqueous layer by simpledecantation, using a separating funnel. 25 g of hydroxylaminehydrochloride dissolved in 50 mL of water was added to the organiclayer, keeping the system at 65° C. under agitation, for three hours andthirty minutes. The organic layer was separated from the aqueous layerby decantation. The product was purified by extraction with isopropylether and concentrated by evaporation of the solvent. These reactionconditions are such as not to reduce the oximes produced from themixture of cardanols of this invention to a single oxime, but insteadproduce a mixture of oximes, either aldoximes or ketoximes as desired,that corresponds to the mixture of cardanols isolated from the naturalcashew nut shell liquid.

[0038] The complexation capacity of this new extractant, can beexemplified by starting from a solution of copper sulphate of knownconcentration, a reaction with the oximes was carried on; immediatelyafter reaction, the copper remaining in solution is measured bytitration.

[0039] The procedure is as follows: Weigh 1 g of oximes. Solubilize themtotally, using as small a volume of amyl alcohol as possible. In aseparating funnel, add 18 ml of CuSO₄ (5 g/L) and mix thoroughly. Letthe layers separate and discard the aqueous layer. To the organic layerwhich contains the extractant and the extracted Cu²⁺, add 14.0 mL ofH₂SO₄, 1:4 v/v to extract the Cu²⁺ back to the aqueous phase.

[0040] The aqueous layer is transferred to a beaker, deonized water isadded (approximately 50 mL) and the solution is neutralized withconcentrated NH₄OH and an excess is added to solubilize all of the Cu²⁺as cupric amino complex. After this , the solution is transferred to aglass graduated cylinder and the final volume is reported. A sample of10.0 mL is transferred to an Erlenmeyer flask and the Cu⁺² is titratedwith standard 0.001N EDTA solution, using murexide as indicator.

[0041] During the experimental trials, it was noticed that during of thecarbonylation reaction of the cardanol mixture, using the classicReimer-Tiemann reaction, very often emulsions were formed during theaddition of the solution of NaOH to the reaction medium constituted ofchloroform and cashew nut shell liquid.

[0042] It was also considered that the double bonds of the alkenylsubstituents present in the mixture of the oximes obtained were probablythe sites where the hydration reaction could be carried onsimultaneously with carbonylation of the benzenic ring.

[0043] To solve the problem of emulsion formation, the double bonds weresaturated by hydrogenation of the cashew nut shell liquid beforereaction. The aim was to eliminate or reduce the possibility of emulsionformation.

[0044] Alternatively, the compounds of the invention can be prepared bya variation of the procedure of Reaction Scheme A, which is depicted inReaction Scheme B:

[0045] After the hydrogenation reaction, the catalyst C/Pd was filteredusing diatomite powder to clarify the product. The filtration wasconducted in Buchner, under reduced pressure at temperature in the rangeof 40-45° C. The hydrogenated cardanol after cooling down to roomtemperature, becomes solid around 28-30° C., in agreement with theliterature.

[0046] The product was characterized as a hydrogenated cardanol by itsRefraction Index and by Infrared spectroscopy.

[0047] During the trials it was observed that the occurrence ofemulsions was greatly reduced, making the operating tasks easier.

[0048] After the reactions, according to Scheme B, there were carried onthe same reactions of carbonylation and oximation as per the followingScheme A:

[0049] The hydrogenation reaction was carried on in a Parr reactor,setting the operational conditions as following: temperature 200° C.,time 2 hours 50 minutes, speed of mechanical stirrer in the range of800-1200 rpm. The aldoxime obtained was evaluated as for its capacity ofcomplexing Cu⁺², using the same method as used for the mixture of oximesproduced as per Scheme A.

[0050] The process of Reaction Schemes A and B can be conducted in abatch fashion. The reactants and reagents may be initially introducedinto the reaction zone batchwise and either intermittently orcontinuously into the reaction zone during the course of the reaction.The addition of NaOH solution into the reaction vessel during theReimer-Tiemann reaction is an example of this procedure.

[0051] The following specific examples are presented to moreparticularly illustrate the invention.

EXAMPLE 1

[0052] 1. Cashew Nut Shell Liquid Pre-Treatment.

[0053] 100 g of cashew nut shell liquid was introduced into adistillation rounded bottom glass vessel to which were adapted acondenser and a thermometer at the top and a receiving glass at the endof the condenser. The apparatus were linked to the vacuum line of thelaboratory and the distillation vessel was supported by an electricmantle. Under vacuum of 10-25 mm Hg, heating was started and increasingslowly until the temperature at the top of the vessel reach 180° C.,when a mist of the CO₂ starts to condense. At this temperature it takesabout 45 minutes to remove all CO₂ by the vacuum system. The temperatureat the top of distillation vessel then rises to 200-230° C., where thefirst fraction was condensed. This first fraction was discarded, afterstopping the vacuum system and the heater. Upon restarting theoperation, when the temperature of vapor at the top the distillationvessel reaches 200-230° C., a mild yellow liquid starts to condense.

[0054] This liquid takes about two hours to be distilled, and thetemperature rises again to 250-280° C., when a red liquid starts tocondense.

[0055] The yellow fraction was separated and characterized by refractiveindex and infrared spectroscopy. By comparison with data in theliterature, it was identified as cardanol.

[0056] 2. Reimer-Tiemann Reaction

[0057] In a rounded bottom glass vessel with three openings, adapted toa refluxing condenser, addition funnel with pressure equalization andprovided with magnetic stirrer, were added at inert atmosphere (N₂ ),45.0 g of chloroform and 100 g of cardanol, just after distillation. Thesystem was heated up to 60° C. and 300 mL of 4.6N sodium hydroxidesolution was added drop by drop, keeping in reflux for six hours andthirty minutes at 70-75° C.

[0058] The organic phase was separated from the aqueous phase.

[0059] 3. Oximation Reaction

[0060] To the organic phase separated in the Reimer Tiemann reactionstep, 25.0 g of hydroxylamine chloride were added, keeping the system at75° C. for three hours and thirty minutes. The organic layer wasseparated of the aqueous layer by simple decantation.

EXAMPLE 2

[0061]1. Cashew Nut Shell Liquid Pre-Treatment.

[0062] 150 g of cashew nut shell liquid was introduced into adistillation rounded bottom glass vessel to which were adapted acondenser and a thermometer at the top and a receiving glass at the endof the condenser. The apparatus were linked to the vacuum line of thelaboratory and the distillation vessel was supported by an electricmantle. Under vacuum of 5 to 10 mm Hg, heating was started andincreasing slowly until the temperature at the top of the vessel reached180° C., when mist of CO₂ started to condense. At this temperature ittakes about 30 minutes to remove all CO₂ by the vacuum system. Thetemperature at the top of distillation vessel then rose to 200-230° C.,where the first fraction was condensed. This first fraction wasdiscarded and the operation was restarted, and when the temperature ofthe vapor at the top of distillation vessel reached 200-230 ° C., a mildyellow liquid started to condense.

[0063] This liquid took about two hours and thirty minutes to bedistilled and the temperature rose again to 250-280° C., when a redliquid started to condense.

[0064] The yellow fraction was separated and characterized by refractiveindex and infrared spectroscopy, which by comparison with data in theliterature, was identified as cardanol.

[0065] 2. Reimer-Tiemann Reaction

[0066] In a rounded bottom glass vessel, adapted to a refluxingcondenser, addition funnel and provided with mechanical stirrer, 50 g ofchloroform and 100 g of cardanol were added just after distillation. Thesystem was heated up to 65° C. and 300 mL of 4.6N sodium hydroxidesolution was added drop by drop, keeping in reflux for nine hours at65-75° C.

[0067] The organic phase was separated from the aqueous phase.

[0068] 3. Oximation Reaction

[0069] To the organic phase separated in the Reimer-Tiemann reactionstep, were added 30 g of hydroxylamine hydrochloride, keeping the systemat 70° C. for four hours. The organic layer was separated of the aqueouslayer by simple decantation.

EXAMPLE 3

[0070]1. Cashew Nut Shell Liquid Pretreatment

[0071] 120 g of cashew nut shell liquid was introduced into adistillation rounded bottom glass vessel to which were adapted acondenser, thermometer and receiving flask. The system was linked to avacuum line and heated by electric mantle. Under a vacuum of 5-10 mmHg,heating was started and increased until the temperature at top of thedistillation vessel reached 180° C., when a mist of CO₂ started tocondense. At this temperature it takes about 35 minutes to remove allCO₂ by the vacuum system. When the temperature at the top ofdistillation vessel rose to 200-230° C., the first fraction wascondensed. This fraction was discarded. Re-starting the operation, amild yellow liquid started to condense, at 200-230° C.

[0072] This liquid took about one hour and forty minutes to completedistillation and the temperature rose again to 250-280° C., when a redliquid started to condense.

[0073] The yellow fraction was separated and characterized by refractiveindex and infrared spectroscopy. By comparison with data in theliterature, it was identified as cardanol.

[0074] 2. Hydrogenation of cashew nut shell liquid

[0075] 150 mL of cardanol immediately after distillation was placed in aParr reactor where 2.32 g of Degussa Catalyst C/Pd 10% were previouslypoured. The reactor was closed and the valve of H₂ was opened, settingthe pressure at 3 atm. (44 psi) and the heater was switched onincreasing the temperature gradually. Agitation was fixed at a range of800-850 rpm until it reached 200° C. Up to 2 hours after reaching 200°C., the speed was kept at 800 rpm. 2 hours after the reaction started(considered when 200° C. was reached) and until 2 hours 50 minutes, theagitation was increased to the range of 900-1200 rpm. The reaction wasstopped at this moment. The hydrogen valve was closed and the mixtureallowed to cool a room temperature.

[0076] The reaction mixture was transferred to a Buchner funnel linkedto the vacuum system of the laboratory. An excess of diatomite powderwas added to the reaction mixture, stirred with a glass rod and filteredslowly. This procedure was carried out at 45° C. The filtered cardanolwas clarified to a yellow to brown color and poured into a stopperedglass. After cooling to room temperature it solidified, taking on a waxyappearance.

[0077] 3. Reimer-Tiemann Reaction

[0078] In a rounded bottom glass vessel with three openings, adapted toaddition funnel with pressure equalization and provided with mechanicalstirrer and condenser, were added 50.0 g of chloroform and 110 g ofcardanol, just after distillation. The system was heated up to 70° C.and a 4.6N sodium hydroxide solution was added drop by drop, keeping inreflux for seven hours at 60-70° C.

[0079] The organic phase was separated from the aqueous phase.

[0080] To the organic phase separated in the Reimer Tiemann reactionstep, were added 30 g of hydroxylamine hydrochloride, keeping the systemat 65-70° C. for five hours. The organic layer was separated of theaqueous layer by simple decantation.

[0081] Characterization:

[0082] Aldoximes were characterized by Infrared Spectroscopy and NuclearMagnetic Resonance (NMR), in the procedures explained in Scheme A, andby Infrared Spectroscopy in Scheme B.

[0083] The results are as follows:

[0084] Scheme A:

[0085] Oxime:

[0086] IR: 1550.0-1714.3 cm⁻¹, stretching vibration typical of bond C═NNMR (CDCl₃): d 6.4-7.4 (3H), 0.6-2.8 (6H)

[0087] Scheme B:

[0088] Oxime:

[0089] IR: 1550-1650 cm⁻¹, stretching vibration typical of bond C═N

[0090] Extraction of Copper:

EXAMPLE 1 Scheme A

[0091] 1 g of oxime from trial number 4 was quantitatively transferredto a beaker and solubilized with as small a volume of amyl alcohol aspossible. In a separating funnel, 18 mL of CuSO₄ (5 g/L ) were added andmixed thoroughly. The layers were allowed to separate and the aqueouslayer was discarded. To the organic layer which contains the extractantand the extracted Cu2+, 14.0 ml H₂SO₄, 1:4 v/v, were added to extractthe Cu²⁺ back to the aqueous phase.

[0092] The aqueous layer was transferred to a beaker, deionized waterwas added (approximately 50 mL) and the solution was neutralized withconcentrated NH₄0H and an excess was added to solubilize all Cu²⁺ ascupric amino complex. After this, the solution was transferred to aglass graduated cylinder and the final volume was reported. A sample of10.0 mL was put in an Erlenmeyer flask and the Cu⁺² was titrated withstandard EDTA 0.001N solution, using murexide as indicator. Extractiongave 49.3 mg Cu⁺²/g oxime.

[0093] The result, after calculations was 49,3 mg Cu⁺²/g oxime.

EXAMPLE 2 Scheme B

[0094] 1 g of oxime from trial number 23 was quantitatively transferredto a beaker and solubilized with the smaller volume of amyl alcohol aspossible. In a separating funnel, add 18 mL of CuSO₄(5 g/L ) and mixthoroughly. The layers were allowed to separate and the aqueous layerwas discarded. To the organic layer which contains the extractant andthe extracted Cu²⁺ was added 14.0 mL of H₂SO₄, 1.4 v/v, to extract theCu²⁺ back to the aqueous phase.

[0095] The aqueous layer was transferred to a beaker, deionized waterwas added (approximately 50 mL)and the solution is neutralized withconcentrated NH₄OH and an excess was added to solubilize all Cu2+ ascupric amino complex. After this, the solution was transferred to aglass graduated cylinder and the final volume was reported. A sample of10.0 mL was put in an Erlenmeyer flask and the Cu⁺² was titrated withstandard 0.001N EDTA solution, using murexide as indicator. Extractiongave 49.6 mg Cu⁺²/g oxime.

[0096] Extraction of Gallium:

[0097] To an amount of Bayer liquor containing a known concentration ofgallium is added an aqueous suspension of the oximes of this invention.The mixture is heated and stirred to produce a complex of the oximeswith the gallium in the Bayer liquor. A strong acid such as hydrochloricor sulfuric is added to the complexed mixture to liberate the galliumions from the complex, and the gallium is isolated from the liberatedextract and smelted to produce gallium metal.

What is claimed is:
 1. A process of preparation of oximes, comprising:preparing a mixture of alkyl-salicyl-aldehydes of allyl phenols byreacting a natural product containing a mixture of allyl phenols with anaqueous solution of sodium hydroxide in a temperature range of 20 to 75°C., using chloroform as reagent and solvent; and preparing an aldoximeor ketoxime by reacting the mixture of alkyl-salicyl-aldehydes or amixture of alkyl-salicyl-ketones derived from the mixture ofalkyl-salicyl-aldehydes with hydroxylamine sulfate, hydroxylaminehydrochloride or other salt of hydroxylamine.
 2. The process accordingto claim 1, wherein the natural product containing a mixture of allylphenols is cashew nut shell liquid.
 3. The process according to claim 1,wherein the natural product comprises an unsaturated cardanol.
 4. Theprocess according to claim 1, wherein the mixture of allyl phenolscomprises anacardic acid, cardanol, cardol and methyl cardol.
 5. Aproduct mixture produced by the process according to claim 1, expressedby the formula:


6. A process for preparing an oxime mixture of the formula:

where R=C₁₅H_(31-n) and n=0, 2, 4 and 6, comprising: (b) preparing analkyl-salicyl-aldehyde of cardanol by reacting a solution of cardanol inchloroform with an aqueous solution of sodium hydroxyde at a temperatureof 20 to 70° C.; and (c) reacting the alkyl-salicyl-aldehyde of cardanolprepared in step (a) with a hydroxylamine salt to produce an oxime ofsaid formula.
 7. The process of claim 6, wherein the hydroxylamine saltis hydroxylarnine sulfate or hydroxylamine hydrochloride.
 8. A processfor the extraction of gallium from an effluent containing gallium,comprising: adding an aqueous suspension of the oxime mixture of claim 5to the effluent containing gallium to produce a complex containinggallium, adding a strong acid to the complex to produce agallium-containing mixture, and isolating gallium from thegallium-containing mixture.
 9. The process according to claim 8, whereinthe effluent is Bayer liquor.
 10. The process according to claim 8,wherein the strong acid is hydrochloric acid or sulfuric acid.